The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. However, such scaling down has also increased the capacitive coupling between adjacent elements. For example, in back-end of line (BEOL) interconnect structures, for any two adjacent conductive lines, when the distance between the conductive lines decreases, the resulting capacitance (a function of the dielectric constant (k value) of the insulating material divided by the distance between the conductive features) increases. This increase in capacitive coupling further results in increased parasitic capacitance, which negatively impacts the speed and overall performance of the IC device.
Improved methods of reducing capacitance between interconnect lines are desired.